private void doCancel(final Dialog dialog) {
    assert TransactionUtils.isTransactionExecutionThread()
        : "Code run in wrong thread. Must be run in TransactionThread. Now in "
            + Thread.currentThread();
    assert !done.get();

    final InviteClntTransaction transaction =
        getTransactionManager().findTransaction(dialog, SIP_INVITE_CLIENT);

    final DialogStateEvent<BaseSipMessage> stateEvent =
        new DefaultDialogStateEvent<BaseSipMessage>(dialog, SessionState.SESSION_TERMINATED, null);

    dialogStateListenerHolder.getNotifier().onSessionTerminated(stateEvent);
    // dialogStateListenerHolder.getNotifier().onSessionEnded(stateEvent);
    // DIALOG.putCustomParameter(ParamKey.INITIAL_MESSAGE, ((Transaction)
    // transaction).getInitialMessage());

    if (transaction != null) {
      transaction.cancel();
    }
  }
  public void handleIncomingCancel(Request msg) throws DialogStateException {
    assert !done.get();
    assert msg != null && MessageType.SIP_CANCEL == MessageType.parse(msg.getMethod());

    if (!done.get()) {
      Logger.log("Remote party has sent SIP_CANCEL");

      final Dialog dialog = getStackContext().getDialogStorage().findDialogForMessage(msg);

      if (dialog != null) {
        dialog.getMessageHistory().addMessage(msg, true);

        final InviteSrvTransaction transaction =
            getTransactionManager().findTransaction(dialog, SIP_INVITE_SERVER);

        if (transaction != null) {
          final DialogStateEvent<BaseSipMessage> stateEvent =
              new DefaultDialogStateEvent<BaseSipMessage>(
                  dialog, SessionState.SESSION_TERMINATED, msg);

          dialogStateListenerHolder.getNotifier().onSessionTerminated(stateEvent);
          dialogStateListenerHolder.getNotifier().onSessionEnded(stateEvent);
          // DIALOG.putCustomParameter(ParamKey.INITIAL_MESSAGE, ((Transaction)
          // transaction).getInitialMessage());

          transaction.cancel();
        } else {
          // assert false : "Transaction already terminated for msg: " + msg.shortDescription() + "
          // dialog: " + dialog;
          throw new DialogStateException(
              dialog, DialogStateException.Error.REQUEST_FOR_UNKNOWN_DIALOG, msg);
        }
      } else {
        // assert false : "Dialog is already terminated or never exist. Message :" +
        // msg.shortDescription();
        throw new DialogStateException(
            dialog, DialogStateException.Error.REQUEST_FOR_UNKNOWN_DIALOG, msg);
      }
    }
  }